Chemical structure of Wyodak coal

The chemical structure of a sub-bituminous coal from the Wyodak seam, Wyoming, has been investigated using the technique of per TFA oxidative degradation. The relative amounts of products differ markedly from those from a typical bituminous coal (Illinois No. 6 seam, Monterey mine).     

Multiple Scales Solution for a Beam with a Small Bending Stiffness

This paper considers the problem of a beam with a small bending stiffness, within the framework of a nonlinear beam model that includes both the classical cable and the linear beam as limiting cases. This problem, treated as a perturbation of the catenary solution, is solved with the multiple scales method. The resulting expressions of the beam deflection and of the internal forces, as well as those obtained with the more commonly applied matched asymptotics method, are compared with numerical results. This comparison indicates that a better accuracy can be achieved with the multiple scales approach, for a similar computational effort. These results also suggest that application of the multiple scales method to the solution of beam problems involving boundary layers extend the range of values of the small parameter, for which accurate analytical solutions can be obtained by a perturbation technique.     

New method for elucidating the structures of coal

A mixture of 30% aqueous hydrogen peroxide (H₂O₂) and trifluoroacetic acid (TFA) dissolves coals to give colourless solutions. Depending on the nature of the coal, 9–55% of the hydrogen in the original coal is converted to simple aliphatic products. The aliphatic products preserve most of the original aliphatic structure of the coal. This technique of oxidative degradation is a powerful method of elucidating the structure of coal. It is particularly applicable to the aliphatic components of coal structure.     

The effects of temperature on the machining of metals

The machining behaviors of metals at various workpiece temperatures are studied by the milling operation. Cutting power was recorded; tool life, chip size, surface finish and the microstructures of chips were examined.     

Arylmethoxyl groups in coal macerals

A method is presented for determining arylmethoxyl groups which involves oxidative degradation with trifluoroperoxyacetic acid. Vitrinites from all coal ranks contain a small and constant amount of arylmethoxyl. There is little if any arylmethoxyl in sporinite or resinite. No arylmethoxyl was detected in fusinite and semifusinite, but the results are less certain because of the insolubility of these macerals in the reagent. The amount of arylmethoxyl in vitrinites is proposed as a measure of the extent of aerobic biodegradation in coalification.     

Chemical signals involved in spacing behavior of breeding female bank voles (Clethrionomys glareolus Schreber 1780, Microtidae,Rodentia)

In order to study the mechanism involved in the seasonal territoriality of breeding bank voles, the social behavior and scent marking of paired females were observed throughout a reproductive cycle. Initially unfamiliar females were kept in large laboratory pens provided with individual burrows. After a brief period of hostility, females behaved in a friendly manner towards each other, sharing the same nest even in the presence of a male and until the middle of pregnancy. They scarcely marked with urine. Continuous olfactory assessment appeared to play an important role in maintaining the friendly interactions. In late pregnant and lactating females, on the contrary, the odor of a familiar female triggered aggressiveness and scent marking with urine and probably with flank glands. These reactions may be interpreted as spacing behavior. Moreover, the interaction between females may inhibit reproduction in one of them. These results are discussed in relation with the available ecological data.     

Dihydroaromatic structure of Illinois No. 6 Monterey coal

Coal from the Monterey mine (Illinois No. 6 seam) has been oxidatively fragmented by trifluoroperoxyacetic acid. The major products were acetic, malonic, and succinic acids; benzene di, tri, tetra; and penta-carboxylic acids; and two compounds provisionally identified as the epoxides of ethylene tri- and tetra-carboxylic acids. These products are in best accord with a structure for Monterey coal in which dihydrobenzene units are frequently interspersed in a polymer composed of condensed aromatic chains and clusters. The methyl and hydroxyl substituents complete the dominant pattern.     

Aryl-alkyl groups in coals

A method has been developed for detecting ethyl, propyl, and isopropyl substituents on aryl rings in coals. This method complements an earlier method for determining aryl-methyl groups. Examination of five coals showed that 0.1-0.3% of the carbon was in aryl-ethyl groups. Aryl-propyl, aryl-isopropyl, and larger aryl-alkyl groups were not detected. Aryl-methyl is the dominant aryl-alkyl group in coals and generally accounts for ≈1% of the carbon.     

Transient Fokker–Planck–Kolmogorov equation solved with smoothed particle hydrodynamics method

Probabilistic theories aim at describing the properties of systems subjected to random excitations by means of statistical characteristics such as the probability density function ψ (pdf). The time evolution of the pdf of the response of a randomly excited deterministic system is commonly described with the transient Fokker–Planck–Kolmogorov (FPK) equation. The FPK equation is a conservation equation of a hypothetical or abstract fluid, which models the transport of probability. This paper presents a generalized formalism for the resolution of the transient FPK equation by using the well‐known mesh‐free Lagrangian method, smoothed particle hydrodynamics). Numerical implementation shows notable advantages of this method in an unbounded state space: (1) the conservation of total probability in the state space is explicitly written; (2) no artifact is required to manage far‐field boundary conditions; (3) the positivity of the pdf is ensured; and (4) the extension to higher dimensions is straightforward. Furthermore, thanks to the moving particles, this method is adapted for a large kind of initial conditions, even slightly dispersed distributions. The FPK equation is solved without any a priori knowledge of the stationary distribution, just a precise representation of the initial distribution is required.Copyright © 2013 John Wiley & Sons, Ltd.